One type of earth boring bit has at least one rotatable cone, typically three. The cones are mounted on depending bearing sections. As the bit body is rotated about the bit axis, each cone rotates about its bearing pin axis. A lubricant chamber supplies lubricant to the bearing spaces between the cone and the bearing pin. A seal adjacent the mouth of the cone seals lubricant from leakage to the exterior as well as sealing bore hole drilling fluid from entering the lubricant chamber.
One type of seal employs metal faces in sliding contact with each other. One of the metal faces is pressed against the other by an elastomeric energizer ring. While successful, some axial play occurs between the bearing pin and the cone, particularly after the bit has been drilling for an extended time. This fluctuating axial play will cause the energizing force supplied by the elastomeric energizing ring to also fluctuate, contributing to leakage and seal failure.
Metal face seals having magnets are commercially available for general industrial applications. These magnets are mounted to one of the seal members to attract the opposite seal member. Applicant is not aware of any earth-boring bits utilizing magnetic metal face seals.